import java.util.Stack;

public class JavaStack implements RPNStack {
	Stack<Double> st = new Stack<Double>();

	public int size() {
		return st.size();
	}

	public void clear() {
		st.clear();
	}

	public boolean empty() {
		return st.empty();
	}

	public void push(double token) {
		st.push(token);
	}

	public double pop() {
		return st.pop();
	}
}
